The ATSC (Advanced Television Systems Committee) developed standards for digital television (DTV) that specify technologies for the transport, format, compression, and transmission of DTV in the United States. For example, so-called “8VSB” is the 8-level vestigial sideband modulation method adopted for terrestrial broadcast of the ATSC digital television standard in the United States and Canada. In the 6 megahertz channel used for broadcasting ATSC, 8VSB carries 19.39 megabits of usable data per second, although the actual transmitted bit rate is significantly higher due to the addition of forward error correction codes. The eight signal levels are selected with the use of a trellis encoder. There are also the similar modulations 2VSB, 4VSB, and 16VSB. 16VSB was notably intended to be used for ATSC digital cable, but quadrature amplitude modulation (QAM) has become the industry standard instead.
ATSC receivers synchronize their operations to a primary signal, and the primary signal is usually the direct signal received over the shortest transmission path. However, so-called multipath signals may similarly be received over other paths that are typically delayed with respect to the primary signal and materialize as lagging echo signals. Echoes signals vary in number, amplitude and delay time from location to location and from channel to channel at a given location.
The presence of echo signals in a multipath environment materially affects the ability of radio frequency receivers, such as ATSC receivers, to properly receive and decode the primary signal. Given that many radio frequency signals can be corrupted by multipath signals, extensive hardware has been developed to cancel out the lesser multipath signals. However, such echo canceling hardware is not always completely successful and signal quality can suffer as a consequence. As such, what is needed is a system and method for improving radio frequency signal reception.